The Acme Battery Company has developed a new cell phone battery. On average, the battery lasts 60 minutes on a single charge. The standard deviation is 4 minutes. Suppose the manufacturing department runs a quality control test. They randomly select 7 batteries. The standard deviation of the selected batteries is 6 minutes. a. What would be the chi-square statistic represented by this test? b. What are the degrees of freedom for the chi-square statistic? c. Suppose they repeated the test with a new random sample of 7 batteries. What is the probability that the standard deviation in the new test would be greater than 6 minutes? (Use the applet)

X² = 13.5

Degree of freedom = 6

0.04

Step-by-step explanation:

Give the following :

Number of samples (n) = 7

Population standard deviation (σ) =.4 minutes

Sample standard deviation (s) = 6

Mean battery life = 60 minutes

A) Chisquare (X²) :

X² = ((n - 1) * s²) / σ²

X² = ((7 - 1) * 6²) / 4²

X² = (6 * 6²) / 4²

X² = (6 * 36) / 16

X² = 216 / 16

X² = 13.5

B.) The degree of freedom:

degree of freedom = n - 1

Degree of freedom = 7 - 1 = 6

C.) using a chisquare distribution calculator :

With degree of freedom (df) = 6

X² = 13.5

Hence,

P(X² > 13.5) = 0.04 ( from calculator)

answer: '

the distance between points l and m

step-by-step explanation:

answer: ratio of volume of cone (with 3 times the height and equal diameter) to volume of cylinder is 2 to 1. the value of π is not used.

step-by-step explanation:

radius is diameter/2 = 4.

area of circle is π r^2.

volume of cylinder is height × area of base = hπr^2 = 3(4^2) π = 48π cubic inches.

not knowing the formula for volume of cone, i calculate it using calculus (which is for calculating things).

volume of cone is integral 0 to h area(y) dy. area(y) is π r(y)^2. r(y) runs r to zero as y runs zero to h, r(0) = r, r(h) = 0.

r(y) = r - r/h y

area(y) = π (r - r/h y)^2 = π (r^2 - 2r^2y/h + r^2y^2/h^2) = π r^2(1-2y/h+y^2/h^2)

antiderivative area(y) = π r^2 (y-y^2/h+y^3/(3h^2))

integral 0 to h = π r^2(h-h^2/h+h^3/(3h^2) - (0)) = π r^2(h - h + h/3) = π r^2(h/3) = π/3 r^2 h

volume of this cone is π/3(4^2)18 cubic inches.

= 6 16 π = 96π cubic inches.

cone has twice the volume, 96/48.

cone height is 6 times the cylinder.

ratio of volume formula: π r^2 cancels.

cone over cylinder ratio is 6h/3 to h, 2 to 1.